As ICRP Publication 16 recommends, the roentgenography should be carried out in exposure to the patient as low as practical. With this respect, in order to reduce the patient dose, dental roentgenography with the intensifying screen was tried. With preliminary experiment it was concluded that the existing screens would be useless for dental roentgenography, because of its great lack of sharpness in image. New intensifying screen (Kyokko BF) which was manufactured with trial by Dainippon Toryo Co., Ltd. would substitute as the non-screen film dental roentgenography when the sharpness of the image is not stirictly required. When BF screen is applied to dental roentgenography exposure is about 80% less as compared with that in the case of non-screen dental roentgenography. The authors acknowledge Professor Dr, Toru Oka, Department of Oral Surgery, Nagoya University school of Medicine, for his kind advice to this research work.
The history of a photo-timer is not so old, in Japan, they began to produce it since 1951,already it has passed 20 years more. The utility photo-timer is limited-furnished on the condencer charged equipments mostly, then recent years, a prectical uses of the photo-timer-furnished transformer equipments are becoming widespread gradually. Although, a saving of the exposing time is the most important problem on a chest photography, capacity of existing timer is not suitable for the photography. Because the case of a long time exposing, theree has not been so many troubles, but moving to a short time exposing, the density irregular should be more increased. Consequently, exception of foreign made IONTMAT, it is the present condition that most of the 3 phase X-ray exposing equipments do not furnish the X-ray value control system on itself. Therefore the reports and references of this system have been very few. So, in our dopartment, we experienced and tried to assemble the photo-timer for chest photography using TRIAC to glade up its accuracy, which is furnished on the equipment made by Siemens GMBH, Germany. Then we were able to obtain sufficient result, and this is our report of the experimentation.
In view of the genetically significant dose of the nation, the reduction of gonad dose has now come most serious problem. It is, however, urgent require for every medical facilities to carry out a sufficient and positive x-ray control to solve this problem. Accordingly, the writer has deviced the following three methods to respond the demand, hereby make a report on the result of obtaining better radiography by overcoming the difficulties of taking the hip joints of infants experienced during past years. 1. The measuring equipment for pubic bones of infants is deviced, which exactly fit to the individual pelvic cavity of the patients, capable for gonad protection accurately and to measure most simply without interferring diagnotical purpose. 2. To possible the above purpose, a special protector is deviced by clayish compound made of mainly sulfate barium. 3. A stabilized x-ray table is made for trial.
The authors studied the optimum density of scintiphotogram for the various organs. The results are following. 1) Density-factor, dot-factor and scanning-speed of the scintillation scanners is changed by the density of scintiphotogram exceedingly. So, we must be understood the changeness of density and must not be too much swayed by the settled idea. 2) The optimum density of scintiphotogram is about 1.0. 3) Clinically, it is doubtfull that we apply to the ratio of the density of scintiphotogram without careful thought. But it will be usefull to conclude with following expression. (ratio of the density of scintiphotogram : [numerical formula])